The Bodele depression at the southern edge of the Sahara is a fearsome, forsaken place. Winds howl through the nearby Tebesti Mountains and Ennedi Plateau, picking up speed as they funnel into a parched wasteland nearly the size of California. Once there was a massive freshwater lake here. Now the lake is a shrunken puddle of its former self. Across most of the landscape, there is nothing.

Or so it would seem. But as the winds sweep the ancient lake bed, which has not been inundated in much of this area for several thousand years, they carry trillions of tiny particles skyward in vast, swirling white clouds. The dust then starts a mysterious journey—or a series of mysterious journeys—that scientists are trying to better understand.